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DIY Speaker Event in Grand Rapids, MI - Sept. 2019

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  • #46
    Room booked and signed up. The site was a little odd, the top event didn't go anywhere but the second one leads to a Google form registration page.

    https://meniscusaudio.com/event/meniscus-audio-css-diy/
    Electronics engineer, woofer enthusiast, and musician.
    Wogg Music
    Published projects: PPA100 Bass Guitar Amp, ISO El-Cheapo Sub, Indy 8 2.1 powered sub, MicroSat, SuperNova Minimus

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    • #47
      I'm excited to see what everyone brings and to spend some time with friends.

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      • #48
        Ed never ceases to blow me away.
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        Byzantium Project & Build Thread || MiniByzy Build Thread || 3 x Peerless 850439 HDS 3-way || 8" 2-way - RS28A/B&C8BG51

        95% of Climate Models Agree: The Observations Must be Wrong
        "Gravitational systems are the ashes of prior electrical systems.". - Hannes Alfven, Nobel Laureate, Plasma physicist.

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        • #49
          The Von-Ottos are looking Von-Awesome! I wish they weren't too big for my space! Looking forward to seeing and hearing them again!

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          • #50
            The attached pic is a preview of what I will be bringing (the two tall things in the foreground).. I have only assembled one speaker so far, and have been doing the crossover development in mono. To give you a sense of scale, the towers are each 5 feet tall and almost 3 feet wide. This is a test platform for a couple of different nude open baffle systems that I want to try out over the winter.

            Source will be a Linux laptop with CD drive. If I can get on WiFi I can stream from the web. I will be using a USB audio interface that has analog and SPDIF inputs. Of course there will be a couple of amps as well and I could use some help during unloading and set up. I may demo these at Meniscus on Friday evening as well.


            Click image for larger version  Name:	CharlieLaub_nude_OB_system.jpg Views:	1 Size:	100.1 KB ID:	1421209
            Charlie's Audio Pages: http://audio.claub.net

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            • #51
              Originally posted by charlielaub View Post
              The attached pic is a preview of what I will be bringing (the two tall things in the foreground).. I have only assembled one speaker so far, and have been doing the crossover development in mono. To give you a sense of scale, the towers are each 5 feet tall and almost 3 feet wide. This is a test platform for a couple of different nude open baffle systems that I want to try out over the winter.

              Source will be a Linux laptop with CD drive. If I can get on WiFi I can stream from the web. I will be using a USB audio interface that has analog and SPDIF inputs. Of course there will be a couple of amps as well and I could use some help during unloading and set up. I may demo these at Meniscus on Friday evening as well.


              Click image for larger version Name:	CharlieLaub_nude_OB_system.jpg Views:	1 Size:	100.1 KB ID:	1421209
              Cool. Look forward to hearing these. Did you use flash to take this picture? I am not seeing a flash reflection in the Plexiglas.
              SideTowers: http://techtalk.parts-express.com/fo...corundum-build
              Totally Flat: http://techtalk.parts-express.com/fo...5-totally-flat
              Plumber's Delight: http://techtalk.parts-express.com/fo...notech-winners
              Linehopper: http://techtalk.parts-express.com/sh...Esoteric-build

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              • #52
                Originally posted by 4thtry View Post

                Cool. Look forward to hearing these. Did you use flash to take this picture? I am not seeing a flash reflection in the Plexiglas.
                This type of system is called a "nude" open baffle. There is no spoon - there is no baffle. It's nude, meaning the drivers are not mounted to anything. Where you are expecting plexiglass there is only air. I have suspended the drivers - the woofer via nylon wires and the tweeters at the end of a strip of plastic mesh. The nude open baffle has some real advantages but presents some crossover design challenges.

                This system has been conceived to have identical forward and rearward radiation, and uses a dipole tweeter arrangement composed of two back-to-back Dayton ND25FW-4. It's a "20-20k dipole" based on some of the principles I have espoused in the attached pdf article.

                One very interesting thing about this kind of speaker is that you can walk around the speakers, to the side, in back of them, etc. and the tonal balance stays exactly the same. You can also listen in the "null" spot between speakers, where the "room sound" consisting primarily of reflections dominates, especially in more live and reflective listening spaces. It's very different from other kinds of speakers.
                Attached Files
                Charlie's Audio Pages: http://audio.claub.net

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                • #53
                  Yes, Charlie, your approach to a no-baffle design is quite different from mine. For one thing, I include a little multi-sensory aesthetic in my design.

                  Ken, I have a pair of those TangBand woofers you are looking for, and am willing to let go of them. I presume you are asking in this thread because you will be in Grand Rapids this weekend, so I plan to bring them with me. I have two pairs, do you want all four?

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                  • #54
                    I'd like to do some calculations of the room modes in the rooms we will be using. I think I remember seeing the dimensions of the room in the hotel on Saturday in the event description on the Meniscus website, but my browser is now not letting me access the page where it is most likely to be. Could someone post here the room dimensions? Even approximately, if you have been to this event before.

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                    • #55
                      Originally posted by charlielaub View Post

                      This type of system is called a "nude" open baffle. There is no spoon - there is no baffle. It's nude, meaning the drivers are not mounted to anything. Where you are expecting plexiglass there is only air. I have suspended the drivers - the woofer via nylon wires and the tweeters at the end of a strip of plastic mesh. The nude open baffle has some real advantages but presents some crossover design challenges.

                      This system has been conceived to have identical forward and rearward radiation, and uses a dipole tweeter arrangement composed of two back-to-back Dayton ND25FW-4. It's a "20-20k dipole" based on some of the principles I have espoused in the attached pdf article.

                      One very interesting thing about this kind of speaker is that you can walk around the speakers, to the side, in back of them, etc. and the tonal balance stays exactly the same. You can also listen in the "null" spot between speakers, where the "room sound" consisting primarily of reflections dominates, especially in more live and reflective listening spaces. It's very different from other kinds of speakers.
                      Charlie, very interesting design and write-up. Just out of curiosity could you share the other drivers you chose.

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                      • #56
                        Originally posted by mcargill View Post
                        I'd like to do some calculations of the room modes in the rooms we will be using. I think I remember seeing the dimensions of the room in the hotel on Saturday in the event description on the Meniscus website, but my browser is now not letting me access the page where it is most likely to be. Could someone post here the room dimensions? Even approximately, if you have been to this event before.
                        This is the first time it's been held in the venue it will be held in on Saturday, so it is new to all of us.

                        Later,
                        Wolf
                        "Wolf, you shall now be known as "King of the Zip ties." -Pete00t
                        "Wolf and speakers equivalent to Picasso and 'Blue'" -dantheman
                        "He is a true ambassador for this forum and speaker DIY in general." -Ed Froste
                        "We're all in this together, so keep your stick on the ice!" - Red Green aka Steve Smith

                        *InDIYana event website*

                        Photobucket pages:
                        http://photobucket.com/Wolf-Speakers_and_more

                        My blog/writeups/thoughts here at PE:
                        http://techtalk.parts-express.com/blog.php?u=4102

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                        • #57
                          Originally posted by Squidspeak View Post

                          Charlie, very interesting design and write-up. Just out of curiosity could you share the other drivers you chose.
                          Each M-frame uses two Eminence Alpha 15A.
                          The "midranges" are Eminence Deltalite II 2515

                          I'm happy to give you more info in person at the event.
                          Charlie's Audio Pages: http://audio.claub.net

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                          • #58
                            Mcargill, PM sent thank you.

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                            • #59
                              Here's the frequency response of my nude open baffle system with M-frame woofer. The measurement was taken indoors, in-room, has about 20Hz resolution, and uses 6th octave smoothing. It's pretty close to my goal of a system having a 20-20k dipolar response pattern.

                              Click image for larger version

Name:	Meniscus NOBM system 18SEPT2019.png
Views:	20
Size:	61.8 KB
ID:	1421739
                              Charlie's Audio Pages: http://audio.claub.net

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                              • #60
                                Wow, very nice! I can't wait to hear these this weekend.
                                Craig

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